It features a single S-Motor. It requires a Battery Box to work. The Servo Motor can move up to 15 steps total (7 to each side with a middle position) with the Speed Remote or the speed dial on 8878 Power Functions Rechargeable Battery Box. Or, it just turns 90 degrees in either direction then snaps back to the centre with a regular remote. This motor is mainly used for steering.

LEGO.com Description

Drive your LEGO® Technic creations to a whole new level with the LEGO Power Functions motor made for the ultimate 4-wheel steering experience. Power through the turns like never before with ultra-realistic steering. Steer your Technic vehicle left, right or straight ahead with any one of 15 steering axle positions. Rotates 90 degrees clockwise or counterclockwise. It’s easy to add 4-wheel steering to your models with the Servo Motor’s front and back power outputs!

Servo Motor features 90-degree rotation clockwise or counterclockwise

Designed for use with LEGO® Technic elements and vehicles

Includes front and back power output ports for easy 4-wheel steering functionality

Steer 90 degrees in either direction with a total of 15 fixed positions!